Vertically‐Aligned Card‐House Structure for Composite Solid Polymer Electrolyte with Fast and Stable Ion Transport Channels

All‐solid‐state lithium batteries (ASSLBs) are highly promising as next‐generation energy storage devices owing to their potential for great safety and high energy density. This work demonstrates that composite solid polymer electrolyte with vertically‐aligned card‐house structure can simultaneously improve the high rate and long‐term cycling performance of ASSLBs. The vertical alignment of laponite nanosheets creates fast and uniform Li+ ion transport channels at the nanosheets/polymer interphase, resulting in high ionic conductivity of 8.9 × 10−4 S cm−1 and Li+ transference number of 0.32 at 60 °C, as well as uniformly distributed solid electrolyte interphase. Such electrolyte is characterized by high mechanical strength, low flammability, excellent structural stability and stable ion transport channels. In addition, the ASSLB cell with the electrolyte and LiFePO4 cathode delivers a high discharge specific capacity of 124.8 mAh g−1, which accounts for 85.6% of its initial capacity after 500 cycles at 1C. The reasonable design through structural control strategy by interconnecting the vertically‐aligned nanosheets open a way to fabricate high performance composite solid polymer electrolytes. By engineering laponite nanosheets to form a vertically‐aligned card‐house structure, composite solid electrolyte with fast and stable ion transport channels is obtained. Lithium deposits uniformly along the channels on lithium anode and forms a homogeneous SEI layer during long‐term cycling process, which contributes to the outstanding cycling stability of all‐solid‐state lithium batteries.